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Abstract:

A high-voltage wideband pulse load is provided. The high-voltage wideband
pulse load includes an internal line, a dielectric substance, and an
external housing. The internal line includes input terminal, connection
electrode and a rod resistor. The resistance of the internal line
linearly increases along the moving direction of an incoming pulse by the
rod resistor. The dielectric substance is coupled to the internal line in
a coaxial structure which covers the exterior of the internal line, and
is configured to have a shape of a non-linearly decreasing external
diameter along the moving direction so that impedance linearly decreases
along the moving direction in contrast with the resistance of the
internal line. The external housing is coupled to the dielectric
substance in a coaxial structure which covers the exterior of the
dielectric substance, and is formed of metal.

Claims:

1. A high-voltage wideband pulse load, comprising: an internal line
provided with a rod resistor, and configured such that resistance of the
internal line is made to linearly increase along a moving direction of an
incoming pulse by the rod resistor; a dielectric substance coupled to the
internal line in a coaxial structure which covers an exterior of the
internal line, and configured to have a shape of a non-linearly
decreasing external diameter along the moving direction so that impedance
linearly decreases along the moving direction in contrast with the
resistance of the internal line; and an external housing coupled to the
dielectric substance in a coaxial structure which covers an exterior of
the dielectric substance, and formed of metal.

2. The high-voltage wideband pulse load as set forth in claim 1, wherein
the high-voltage wideband pulse load has predetermined characteristic
impedance corresponding to total impedance, the total impedance
determined by the resistance of the internal line and the impedance of
the dielectric substance.

3. The high-voltage wideband pulse load as set forth in claim 2, wherein
the dielectric substance has the external diameter which is non-linearly
decreases based on an exponential function in which an exponent is
determined using the impedance.

4. The high-voltage wideband pulse load as set forth in claim 3, wherein
the external diameter of the dielectric substance is proportional to a
diameter of the internal line.

5. The high-voltage wideband pulse load as set forth in claim 2, wherein
the dielectric substance comprises slits, which allow a length of surface
of the dielectric substance to be extended, around an input terminal.

6. The high-voltage wideband pulse load as set forth in claim 5, wherein
the input terminal is connected to the rod resistor using a connection
connector, and is configured to transmit the incoming pulse from an
external terminal to the rod resistor through the connection connector.

7. The high-voltage wideband pulse load as set forth in claim 6, wherein
the connection connector has an end of diameter which is equal to a
diameter of the rod resistor to prevent impedance mismatching.

8. The high-voltage wideband pulse load as set forth in claim 6, wherein
the input terminal is coupled to the external terminal using one or more
slits.

9. The high-voltage wideband pulse load as set forth in claim 1, wherein
the internal line is connected to a ground using a blot which penetrates
through a metal plate connected to the rod resistor.

Description:

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Korean Patent Application
No. 10-2011-0048715, filed on May 23, 2011, which is hereby incorporated
by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention relates generally to a high-voltage wideband
pulse load, and, more particularly, to a high-voltage wideband pulse
termination load which has the wideband frequency performance of a
high-voltage pulse.

[0004] 2. Description of the Related Art

[0005] FIG. 1 is a view illustrating a prior art high-voltage load.

[0006] As shown in FIG. 1, a high-voltage load 10 includes a plurality of
ceramic resistive elements 11 which are arranged in a stacked structure
on a coaxial line, and includes a cable termination device 12 which
terminates input impedance to 50 ohm.

[0007] The high-voltage load 10 includes an HN connector 13 which
functions as an input terminal, and includes a dielectric substance 14
which is composed of oil in order to have insulation resistance.

[0008] Such a ceramic resistive element 11 is physically 1 inch long. The
oil is not treated inside the ceramic resistive element, and a space
between an internal electrode, which forms a high-voltage potential, and
an earth line is filled with air.

[0009] However, since the internal diameter and external diameter of the
high-voltage load 10 are designed to correspond to specific impedance,
the external diameter of the HN connector 13 is not large enough to have
high-voltage insulation resistance because of the restricted internal
diameter. Therefore, when a pulse of dozens of kV is received, a
dielectric breakdown phenomenon may occur in the HN connector 13.
Further, since the gaps of the ceramic resistive elements 11 which are
connected in parallel are filled with air, a dielectric breakdown may
occur because of the corona phenomenon which is generated at high
voltage.

[0010] As described above, there is a problem because it is difficult to
use the prior art high-voltage load 10 as a high-voltage pulse load.

[0012] As shown in FIG. 2, the coaxial cable load 20 is configured in such
a way that the radius of the external housing 22 which covers a central
electrode 21 gradually decreases such that the impedance of a coaxial
line gradually decreases in a longitudinal direction, and that a
resistive material 24 is deposited on the surface of a dielectric
substance 23 in order to form a sheet resistor.

[0013] In the coaxial cable load 20, heat energy which is absorbed into
the sheet resistor is easily transmitted to the external housing 22 which
has a good thermal radiation metal structure, so that the heat energy may
be air-cooled and annihilated.

[0014] The key idea of the coaxial cable load 20 in the aspect of
structural characteristic is that of deposited sheet resistance on the
surface between dielectrics and external housing, but has the problem in
that it is difficult to deposit the sheet resistor regularly having
wanted specific impedance, thereby being difficult to implement target
impedance accurately.

[0015] As described above, in order to implement a termination load of an
operational frequency domain of several GHz or higher and a high-voltage
pulse of dozens of kV, both wideband frequency performance and high
insulation voltage performance should be satisfied at the same time.
However, since the characteristics of the two performances conflict with
each other, it is difficult to solve the problem using the prior art
technology.

SUMMARY OF THE INVENTION

[0016] Accordingly, the present invention has been made keeping in mind
the above problems occurring in the prior art, and an object of the
present invention is to provide a high-voltage wideband pulse load which
has wideband frequency performance and high-voltage insulation resistance
performance at the same time in order to test a high-voltage fast
transient pulse.

[0017] In order to accomplish the above object, the present invention
provides a high-voltage wideband pulse load, including an internal line
provided with a rod resistor which has resistance corresponding to
predetermined characteristic impedance, and configured such that the
resistance of the internal line is made to linearly increase along the
moving direction of an incoming pulse by the rod resistor; a dielectric
substance coupled to the internal line in a coaxial structure which
covers the exterior of the internal line, and configured to have a shape
of a non-linearly decreasing external diameter along the moving direction
so that impedance linearly decreases along the moving direction in
contrast with the resistance of the internal line; and an external
housing coupled to the dielectric substance in a coaxial structure which
covers the exterior of the dielectric substance, and formed of metal.

[0018] Here, total impedance, which is determined using the resistance of
the internal line and the coaxial impedance of the dielectric substance,
may correspond to the characteristic impedance.

[0019] Further, the dielectric substance may have a shape in which the
external diameter thereof non-linearly decreases based on an exponential
function in which an exponent is determined using the coaxial impedance.

[0020] Further, the external diameter of the dielectric substance may be
proportional to a diameter of the internal line.

[0021] Further, the dielectric substance may include slits, which allow
the length of the surface of the dielectric substance to be extended,
around an input terminal.

[0022] Further, the input terminal may be connected to the rod resistor
using a connection connector, and may be configured to transmit the pulse
which flows through an external terminal to the rod resistor using the
connection connector.

[0023] Further, the diameter of the connection connector is equal to the
diameter of the rod resistor in order to prevent a pulse transmitted to
the rod resistor from being dispersed or reflected.

[0024] Further, the internal line may further include the input terminal
and the connection connector, and the total impedance may correspond to
the coaxial impedance in a section from the input terminal to the
connection connector.

[0025] Further, the input terminal may be coupled to the external terminal
using one or more slits.

[0026] Further, the internal line may be connected to a ground using a
blot which penetrates through a metal plate connected to the rod
resistor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present
invention will be more clearly understood from the following detailed
description taken in conjunction with the accompanying drawings, in
which:

[0030]FIG. 3 is a longitudinal section view illustrating a high-voltage
wideband pulse load according to an embodiment of the present invention;

[0031] FIG. 4 is a cross sectional view illustrating a high-voltage
wideband pulse load according to an embodiment of the present invention;

[0032] FIG. 5 is a view illustrating the impedance characteristics of the
load according to the embodiment of the present invention;

[0033] FIG. 6 is a view illustrating the structure of the connection
scheme of input terminal according to an embodiment of the present
invention:

[0034]FIG. 7 is a view illustrating the impedance characteristics of the
frequency domain of the load according to an embodiment of the present
invention; and

[0035]FIG. 8 is a view illustrating the impedance characteristics of the
time domain of the load according to an embodiment of the present
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The present invention will be described in detail with reference to
the accompanying drawings below. Here, in cases where the description
would be repetitive and detailed descriptions of well-known functions or
configurations would unnecessarily obscure the gist of the present
invention, the detailed descriptions will be omitted. The embodiments of
the present invention are provided to complete the explanation of the
present invention to those skilled in the art. Therefore, the shapes and
sizes of components in the drawings may be exaggerated to provide a more
exact description.

[0037] A high-voltage wideband pulse load according to embodiments of the
present invention will be described with reference to the accompanying
drawings below.

[0038] First, a high-voltage wideband pulse load according to an
embodiment of the present invention will be described with reference to
FIGS. 3 and 4.

[0039]FIG. 3 is a longitudinal section view illustrating a high-voltage
wideband pulse load according to an embodiment of the present invention,
and FIG. 4 is a cross sectional view illustrating the high-voltage
wideband pulse load according to an embodiment of the present invention.

[0040] As shown in FIGS. 3 and 4, a load 100 according to the embodiment
of the present invention is used to terminate a high-voltage pulse, which
has a peak voltage of dozens of kV, a rising time of several ns or less,
a pulse width of several ns or less and a pulse repetition frequency of
several kHz or less, into 50 ohm or a predetermined characteristic
impedance. The load 100 includes an internal line 110, a dielectric
substance 120, a metal plate 130, a bolt 140, and an external housing
150.

[0041] A high-voltage pulse propagates through the internal line 110 in
the longitudinal direction, and the internal line 110 is formed by
sequentially connecting an input terminal 111, a connection connector 113
and a solid resistor 115.

[0042] The input terminal 111 includes engagement slits which are formed
at one end and are used to connect an external terminal, and includes a
mechanical element which is formed at a remaining end and is used to
connect the connection connector 113. Here, the input terminal 111 may
include the mechanical element in the form of a bolt on which external
threads are formed at the remaining end.

[0043] The connection connector 113 includes a mechanical element 111
which is formed at one end and is used to connect the input terminal, and
the remaining end of the connection connector 113 is electrically
connected to the solid resistor 115. Here, the remaining end of the
connection connector 113 has the same diameter as the solid resistor 115.
Further, the connection connector 113 may include a mechanical element in
the form of a bolt on which external threads are formed at the one end.

[0044] Here, when the diameter of the connection connector 113 is
different from that of the solid resistor 115 in the connection region
thereof, it is difficult to obtain wideband frequency performance because
an impedance mismatching is happened when a pulse is transmitted from the
connection connector 113 to the solid resistor 115, and a flinging pulse
and a reflecting pulse are generated at the impedance mismatched area.
Therefore, the diameter of the connection connector 113 should be the
same as that of the solid resistor 115.

[0045] The solid resistor 115 has the shape of a rod. The one end of the
solid resistor 115 is coated with a conductive material in order to form
an electrical connection with the connection connector 113, and the
remaining end of the solid resistor 115 is connected to the bolt 140,
which penetrates through the metal plate 130, in order to connect to the
ground. Here, when the bolt 140 is screwed, the solid resistor 115 is
squeezed in the direction of the connection connector 113, so that the
solid resistor 115 may be electrically connected to the connection
connector 113. Here, the solid resistor 115 corresponds to a carbon rod
resistor, and has a length which is longer than the wavelength of an
incoming pulse. Preferably, the solid resistor 115 may have a length of 5
cm or longer.

[0046] The solid resistor 115 may be analyzed as a distributed element
rather than a lumped element because the physical length of the solid
resistor 115 is longer than the length of an incoming pulse, may have the
same sheet resistance for all the surface area, and may have resistance
which linearly increases when a pulse comes in and propagates in the
longitudinal direction.

[0047] The dielectric substance 120 has the dielectric permittivity
determined based on the material thereof, and is coupled to the internal
line 110 while covering the internal line 110 in a coaxial structure.
Here, the dielectric substance 120 includes carved slits 121 formed in a
ring shape around the input terminal 111, so that the length of the
surface of the dielectric substance, which is necessary to provide
insulation, is increased, thereby improving the insulation resistance
performance for a high-voltage pulse having a peak voltage of dozens of
kV or greater.

[0048] The external housing 150 corresponds to a ground electrode formed
of metal, and is coupled to the dielectric substance 120 while covering
the dielectric substance 120 in a coaxial structure.

[0049] Here, the diameter D of the dielectric substance 120 which covers
the solid resistor 115 is determined as Equation 1 such that the
dielectric substance 120 has characteristic impedance which is
predetermined for all the spots of the load 100 by complementing the
feature of the impedance distribution of the solid resistor 115.

where, "Z" indicates the coaxial impedance of a line, "μ0" indicates
permeability in a vacuum, "μr" indicates the relative permeability of
the dielectric substance 120, ".di-elect cons.0" indicates dielectric
permittivity in a vacuum, ".di-elect cons.r" indicates relative
permittivity of the dielectric substance 120, "D" indicates the diameter
of the dielectric substance 120, and "d" indicates the diameter of the
internal line 110.

[0050] The diameter D of the dielectric substance 120 may be expressed as
Equation 2 using Equation 1.

D = d 10 Z r 138 ( 2 ) ##EQU00002##

[0051] Based on Equation 2, when the coaxial impedance of the dielectric
substance 120 linearly decreases, the diameter D of the dielectric
substance 120 which covers the solid resistor 115 may be determined based
on an exponential function in which an exponent relates to the coaxial
impedance of the dielectric substance 120 and the dielectric permittivity
of the dielectric substance 120. Here, the diameter D of the dielectric
substance 120 which covers the solid resistor 115 is proportional to the
diameter of the internal line 110.

[0052] Therefore, when the coaxial impedance of the dielectric substance
120 linearly decreases, the diameter D of the dielectric substance 120
which covers the solid resistor 115 decreases based on the exponential
function, so that the dielectric substance 120 which covers the solid
resistor 115 has a shape in which the diameter thereof non-linearly
decreases.

[0053] In Equation 1, "C" indicates equivalent capacitance formed on the
differential area between the input terminal 111 and the ground when the
input terminal 111 is separated from the ground using a medium, having a
specific dielectric permittivity, as a boundary. "C" is determined using
the following Equation 3:

C = 2 π 0 r ln ( D d ) ( 3 )
##EQU00003##

[0054] In Equation 1, "L" indicates the equivalent inductance of the
differential length in the coaxial cable structure which includes the
internal line 110 and the dielectric substance 120. "L" is determined
based on Equation 4.

L = μ 0 μ r 2 π ln ( D / d )
( 4 ) ##EQU00004##

[0055] Next, the impedance characteristics of the coaxial structure of the
load according to an embodiment of the present invention will be
described with reference to FIG. 5.

[0056] FIG. 5 is a view illustrating the impedance characteristics of the
load according to the embodiment of the present invention.

[0057] As shown in FIG. 5, the resistance of the internal line 110 is 0
ohm in a section where the connection connector 113 is connected to the
internal line 110, linearly increases in a section where the solid
resistor 115 is connected to the internal line 110, and becomes 50 ohm,
corresponding to the characteristic impedance of the load 100, at the end
of the internal line 110.

[0058] Meanwhile, the impedance of the dielectric substance 120 is 50 ohm
in a section where the dielectric substance 120 covers the connection
connector 113, linearly decreases in a section where the dielectric
substance 120 covers the solid resistor 115, and becomes 0 ohm at the end
of the dielectric substance 120.

[0059] Here, the total impedance of the load 100 is determined based on
the resistance of the internal line 100 and the impedance of the
dielectric substance 120. Therefore, the impedance of the load 100 is
predetermined characteristic impedance for all domains.

[0060] Next, the structure of the connection scheme of input terminal
according to an embodiment of the present invention will be described
with reference to FIG. 6.

[0061] FIG. 6 is a view illustrating the structure of the connection
scheme of input terminal according to an embodiment of the present
invention.

[0062] As shown in FIG. 6, the input terminal 111 includes engagement
slits which are formed at one end and are used to combine with an
external terminal, and includes a mechanical element which is formed at a
remaining end and is formed in a bolt shape on which external threads are
formed.

[0063] Here, the input terminal 111 may include slits, which form end
portions of a cross when viewed from cross section, in order to improve
the force of the connection with the external terminal. Therefore, the
input terminal 111 is formed of a material having elastic force, and is
easily coupled to the external terminal using the slits which are formed
at the end portions of the cross.

[0064] Next, the impedance characteristics of a load according to an
embodiment of the present invention will be described with reference to
FIGS. 7 and 8.

[0065]FIG. 7 is a view illustrating the impedance characteristics of the
frequency domain of the load according to an embodiment of the present
invention.

[0066] The impedance characteristics of the load 100 may be expressed
using a ratio of an input pulse to a reflecting pulse in a frequency
domain by measuring a small signal scattering para meter.

[0067] As shown in FIG. 7, the impedance characteristics of the frequency
domain of the load 100 is a return loss of -20 dB or less in a wide
frequency bandwidth of 10 GHz or greater.

[0068]FIG. 8 is a view illustrating the impedance characteristics of the
time domain of the load according to an embodiment of the present
invention.

[0069] The characteristic of the impedance of the time domain of the load
100 may be expressed using impedance in the time domain using a Time
Domain Reflectometer (TDR).

[0070] As shown in FIG. 8, when the load 100 is manufactured to have an
impedance of 50 ohm, it can be seen that the impedance characteristics of
the time domain of the load 100 has the performance which falls within a
change rate of 5% based on 50 Ohm.

[0071] As described above, the load 100 has the impedance characteristics,
which are matched to 50 ohm in a frequency bandwidth of 0 to 10 GHz.

[0072] According to the embodiment of the present invention, the physical
length of a rod resistor is far longer than the wavelength of an input
pulse, so that resistance linearly increases in the longitudinal
direction of the rod resistor. Therefore, the present invention has the
advantage of complementing the characteristics of the rod resistor in
which the coaxial characteristic impedance linearly increases in the
longitudinal direction by gradually decreasing a ratio of an internal
diameter to an external diameter, the ratio being fixed in a coaxial
structure. Therefore, there is the advantage in that desired
characteristic impedance may be maintained in all the areas of a load in
a coaxial structure.

[0073] Further, when the high-voltage pulse load according to the
embodiment of the present invention is used, there is the advantage in
that the waveform of a high-voltage pulse can be tested using a
capacitive pulse divider or a probe apparatus instead of an expensive
pulse attenuator.

[0074] Although the preferred embodiments of the present invention have
been disclosed for illustrative purposes, those skilled in the art will
appreciate that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the invention as
disclosed in the accompanying claims.

Patent applications by Kyung Hoon Lee, Daejeon KR

Patent applications by Seung Kab Ryu, Daejeon KR

Patent applications by Electronics and Telecommunications Research Institute

Patent applications in class DISSIPATING TERMINATIONS FOR LONG LINES

Patent applications in all subclasses DISSIPATING TERMINATIONS FOR LONG LINES